Powder mixtures having a cellulose ether binder are used in forming articles of various shapes. For example ceramic or metal powder mixtures are formed into honeycombs which are used as substrates in catalytic and adsorption applications. The mixtures must be well blended and homogeneous in order for the resulting shaped body to have good integrity in size and shape and uniform physical properties. The mixtures have organic additives in addition to the binders. These additives can be surfactants, lubricants, and dispersants and function as processing aids to enhance wetting thereby producing a uniform batch.
A major and ongoing need in extrusion of bodies from highly filled powder mixtures, especially multicellular bodies such as honeycombs is to extrude a stiffer body without causing higher pressures. The need is becoming increasingly critical as thinner walled cellular structures are becoming more in demand for various applications. Thin walled products with current technology are extremely difficult to handle without causing shape distortion. Rapid-setting characteristics are important for honeycomb substrates. If the cell walls of the honeycomb can be solidified quickly after forming, the dimension of the greenware will not be altered in subsequent cutting and handling steps. This is especially true for a fragile thin-walled or complex shaped product, or a product having a large frontal area.
The present invention fills the need for rapid setting of extruded bodies which is especially beneficial for thin walled honeycombs.